Temperature sensor using aluminum capillary

Abstract

A temperature sensor assembly is provided. The temperature sensor includes an aluminum capillary soldered to an actuation unit. The actuation unit operably fluidly couples to the capillary to define an internal cavity storing a working fluid. The working fluid configured to manipulate the actuation unit when the working fluid changes temperature. Solder sealingly couples the capillary to the actuation unit.

What is claimed is: 
     
         1 . A temperature sensor assembly comprising:
 an aluminum capillary;   an actuation unit operably fluidly coupled to the capillary, the aluminum capillary and actuation unit defining an internal cavity storing a working fluid, the working fluid configured to manipulate the actuation unit when the working fluid changes temperature; and   solder sealingly coupling the capillary to the actuation unit.   
     
     
         2 . The temperature sensor assembly of  claim 1 , wherein the actuation unit is a bellows; and
 the solder sealingly couples the capillary to the bellows such that the working fluid can actuate the bellows.   
     
     
         3 . The temperature sensor assembly of  claim 2 , further comprising a sensor body, the solder seals an open end of the capillary to an internal surface of the sensor body and also seals an open end of the bellows to the internal surface of the sensor body to sealingly couple the bellows to the capillary. 
     
     
         4 . The temperature sensor assembly of  claim 3 , wherein the bellows is made from a phosphorous bronze; and
 wherein the sensor body is made from a material selected from the group consisting of: a tin plated steel and aluminum.   
     
     
         5 . The temperature sensor of assembly  claim 2 , wherein the solder is a Zn/Al solder. 
     
     
         6 . The temperature sensor of assembly  claim 5 , wherein the Zn/Al solder has about 85 to 99% of Zn, and about 1 to 15% of Al. 
     
     
         7 . The temperature sensor assembly of  claim 6 , wherein the Zn/Al solder includes about 98+/−0.5% of Zn and about 2.0+/−0.5% of Al. 
     
     
         8 . The temperature sensor assembly of  claim 6  further comprising a sensor body defining an internal cavity in which the bellows is positioned, the sensor body being made from a material selected from the group consisting of: a tin plated steel and aluminum;
 wherein the bellows is made from a phosphorous bronze; and 
 the solder sealing the capillary to the sensor body and sealing the sensor body to an open end of the bellows to sealingly couple the capillary to the bellows. 
 
     
     
         9 . The temperature sensor assembly of  claim 2 , wherein the solder is a Sn/Zn solder. 
     
     
         10 . The temperature sensor assembly of  claim 9 , wherein the Sn/Zn solder has about 85 to 99% of Sn, and about 1 to 15% of Zn. 
     
     
         11 . The temperature sensor assembly of  claim 10 , wherein the Sn/Zn solder has about 98+/−0.5% of Sn and about 2.0+/−0.5% of Zn. 
     
     
         12 . The temperature sensor assembly of  claim 11  further comprising a sensor body defining an internal cavity in which the bellows is positioned, the sensor body being made from a material selected from the group consisting of: a tin plated steel and aluminum;
 wherein the bellows is made from a phosphorous bronze; and 
 the solder sealing the capillary to the sensor body and sealing the sensor body to an open end of the bellows to sealingly couple the capillary to the bellows. 
 
     
     
         13 . The temperature sensor assembly of  claim 2 , wherein the solder is a Sn/Cu/Ag solder. 
     
     
         14 . The temperature sensor assembly of  claim 13 , wherein the Sn/Cu/Ag solder has about 99%±0.1% of Sn, about 0.8±0.1% of Cu and 0.2±0.1% of Ag. 
     
     
         15 . The temperature sensor assembly of  claim 14  further comprising a sensor body defining an internal cavity in which the bellows is positioned, the sensor body being made from a material selected from the group consisting of: a tin plated steel and aluminum;
 wherein the bellows is made from a phosphorous bronze; and 
 the solder sealing the capillary to the sensor body and sealing the sensor body to an open end of the bellows to sealingly couple the capillary to the bellows. 
 
     
     
         16 . A thermostat comprising:
 a switch assembly;   a temperature sensor assembly comprising:
 an aluminum capillary; 
 an actuation unit operably fluidly coupled to the capillary, the aluminum capillary and actuation unit defining an internal cavity storing a working fluid, the working fluid configured to manipulate the actuation unit when the working fluid changes temperature; and 
 solder sealingly coupling the capillary to the actuation unit; 
   wherein the actuation unit operably controls the switching unit in response to changes in temperature of the aluminum capillary.   
     
     
         17 . A method of forming a temperature sensor comprising:
 soldering an aluminum capillary to an actuation unit to operably fluidly coupled the capillary to the actuation unit such that the capillary and actuation unit define an internal cavity storing a working fluid, the working fluid configured to manipulate the actuation unit when the working fluid changes temperature.   
     
     
         18 . The method of  claim 17 , wherein the step of soldering is performed by either brazing or induction heating. 
     
     
         19 . The method of  claim 17 , wherein the actuation unit is a bellows formed from a phosphorous bronze and the solder is selected from the group consisting of:
 a Zn/Al solder having about 85 to 99% of Zn, and about 1 to 15% of Al;   a Sn/Zn solder having about 85 to 99% of Sn, and about 1 to 15% of Zn; and   a Sn/Cu/Ag solder having about 99%±0.1% of Sn, about 0.8±0.1% of Cu and 0.2±0.1% of Ag.   
     
     
         20 . The method of  claim 19 , wherein:
 the bellows is made from a phosphorous bronze;   the step of soldering includes soldering an open end of the capillary to a sensor body defining an internal cavity in which the bellows is positioned, the sensor body being made from a material selected from the group consisting of: a tin plated steel and aluminum; and   the step of soldering also includes soldering an open end of the bellows to the sensor body to sealingly couple the capillary to the bellows and form the internal cavity in which the working fluid is stored.